Hydrogenolysis of glycerol on bimetallic Pd-Cu/solid-base catalysts prepared via layered double hydroxides precursors

Abstract

A series of bimetallic Pd-Cu/solid-base catalysts were prepared via thermal decomposition of Pd x Cu 0.4Mg 5.6− x Al 2(OH) 16CO 3 layered double hydroxides precursors and used in hydrogenolysis of glycerol to 1,2-propanediol (1,2-PDO). X-ray diffraction (XRD), scanning electron microscopy (SEM) and N 2O oxidation and followed H 2 titration characterizations confirmed that well structured layered double hydroxides Pd x Cu 0.4Mg 5.6− x Al 2(OH) 16CO 3 crystals could be prepared when the amount of added Pd was less than x < 0.04. Pd and Cu dispersed highly in reduced Pd x Cu 0.4/Mg 5.6− x Al 2O 8.6− x and Pd improved the reduction of Cu. Hydrogenolysis of glycerol proceeded easily on bimetallic Pd-Cu/solid-base catalysts than separated Pd and Cu. On Pd 0.04Cu 0.4/Mg 5.56Al 2O 8.56, the conversion of glycerol and selectivity of 1,2-PDO reached 88.0 and 99.6%, respectively, at 2.0 MPa H 2, 180 °C, 10 h in ethanol solution. And this catalyst is stable in five recycles. It was concluded that H 2-spillover from Pd to Cu increased the activity of Pd x Cu 0.4/Mg 5.6− x Al 2O 8.6− x in hydrogenolysis of glycerol.